What is security in the twenty-first century? Recently, issues such as crime, terrorism, energy security, population movements and migration, environmental and climate security, underdevelopment, health and pandemic diseases, as well as economic security have become important matters of European security. Furthermore, more traditional security challenges, such as military conflicts and the proliferation of weapons of mass destruction (WMDs), have evolved and changed character. In this context, an increasing body of scholarship has recognized the European Union (EU) as a security actor, which is well equipped to tackle these complex security challenges, due to the multi-dimensional or structural character of its policies.Based on a broad definition of security, this unprecedented series examines the role of Europe in international security and justice matters. Taking inspiration from the European Security Strategy (ESS), it identifies more traditional security threats such as WMDs, but also points to global warming and poverty as the possible cause of conflict. Moreover, the series promises to recognize the intrinsic links between security and justice from a multitude of disciplinary perspectives and provides a platform for research that focuses on the study of Europe as a whole, going beyond only the European Union.